Wind Turbines Offshore Netherlands Open to Sea Life

Offshore wind developer Vattenfall and De Rijke Noordzee (The Rich North Sea) are jointly investigating the effect of water replenishment holes in wind turbine foundations on the surrounding sea life.


The research is being carried out on Vattenfall’s 1.5 GW Hollandse Kust Zuid wind farm, the world’s first subsidy-free offshore wind farm. Hollandse Kust Zuid will also become the world’s largest operational offshore wind farm once commissioned in 2023.

All 140 of the wind farm’s turbine monopile foundations are manufactured with elliptical openings located above the seabed and just below the water surface, which are approximately 30 centimetres by 1 metre in size.

Source: Vattenfall

The openings are envisaged as water replenishment holes in the hollow foundations of the wind turbines. These holes ensure that the water in the foundation flows well and is refreshed.

The openings are also expected to allow fish and other sea life such as anemones, crabs, and shrimps to enter the wind turbine foundations and potentially use them as shelter or to find food.

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De Rijke Noordzee has already carried out the first measurements at the site and the research is expected to continue.

The investigations are focused on assessing whether the living conditions, such as oxygen content and temperature, are suitable for the development of marine life in the foundations.

The investigations will also cover the differences between the conditions inside and outside the foundations, as well as how marine life will develop in this environment over time.

”If our expectations come true, it will boost biodiversity under water. Building with nature is the future. I am proud that we are working with Vattenfall on these kinds of innovative solutions, with which we provide our country with sustainable energy and strengthening nature at the same time,” said Erwin Coolen, Program Director at De Rijke Noordzee.

According to Vattenfall, this is the first time research is being carried out to determine how water replenishment holes can improve marine life at offshore wind farms.

”Offshore wind is currently growing rapidly and will continue to expand significantly in the coming years. We are constantly looking for ways to minimize the impact on the ecosystem. by renewing and adapting our wind turbines, we are able to find an increasingly better combination between sustainably produced electricity and a healthy ecosystem,” Vattenfall’s Gijs Nijsten, Head of Permits, Sustainability & Communications on the Hollandse Kust Zuid project, said.

The project is also supported by the Royal Netherlands Institute for Sea Research (NIOZ) and Wageningen Marine Research (WMR).

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